Ed, yes I think that is another way to find out before your statement posts. Could be hard to decipher though if you use your card a lot.
markr867, I'm thinking that you can go to "Activities and Statements" -there it will show posted transactions since last statement. At bottom of transactions it will show dollar amount and rewards earned since last statement (for card use). Subtract that rewards earned amount from your "miles earned since last statement" and that will be total participation miles you were award on the 1st for the previous month....(I think...) ;)
The community miles posted to my Arrival + account on Monday. My account did not say anything about Participation Miles, it just added my credit card miles and Community Miles to my account total.
gefe57, Participation miles are only specifically listed on the statement once monthly from what I can see. So it will be statement time before you see the exact total participation miles listed that were awarded on the 1st for November.